Abstract: A method for treating a mineral composition containing iron, arsenic or other Group VA compounds comprises milling the mineral composition to a particle size of P80 of less than 25 ?m and leaching the mineral composition in the presence of lime and/or limestone and a soluble alkali complexing agent and in the presence of an oxygen containing gas at a pH in the range of from 3.5 to 6.

Abstract: A method and system are provided in which a gold and/or silver-collecting resin-in-leach circuit comprises both co-current and counter-current sections.

Abstract: The present invention relates to methods for recovering precious metals including silver and gold, rare metals including indium and gallium, base metals including copper, lead and zinc or a combination of precious, rare and base metals from complex oxide ores, sulfide ores or oxide and sulphide ores using an acid chloride oxidizing leach.

Abstract: A processes for the regeneration of a silver nitrate and nitric acid based electrolyte as used in certain silver refining processes is based on the hydrolytic removal of undesired metal-based compounds such as water insoluble hydrolysable base metal cations and water insoluble hydrolysable base metal nitrates from which the soluble silver nitrate and nitric acid based electrolyte may be separated. Water is added slowly to a dewatered electrolyte melt held at a predetermined, elevated, temperature while allowing nitric acid thereby formed to evolve and be separated from the melt while the water insoluble base metal salts are formed. The melt is then diluted with water to dilute the silver nitrate contained therein and the insoluble base metal salts are separated from the mixture by filtration.

Abstract: The present invention is directed to a precious metal recovery process in which basic ferric sulphates and/or jarosites are controlled by hot curing of the autoclave discharge slurry followed by decomposition of argentojarosite using strong acid consumers.

Abstract: A method of reducing or preventing the amount of iron sludge or precipitate that forms as a result of the recovery of silver from chemical solutions, such as a standard photographic solution. The method generally involves the introduction of a source of a conjugate organic base, such as a weak organic acid like citric acid or a salt of the conjugate organic base like a citrate salt, to the chemical fluid either before or during the silver recovery process. Preferably the source of conjugate organic base is introduced by combining it with a binder to form a time release cake or placing it in a container that has a semipermeable membrane that maintains the concentration of the conjugate organic base in the chemical fluid from about 0.2 to about 78 milimolar over a period of time.

Abstract: Disclosed is an improved process for making highly dispersible, spherical silver particles. In particular, the invention is directed to a process for making silver particles, which are very high solids and highly ordered. The silver particles formed are particularly useful in electronic applications.

Abstract: Precious metals such as gold can be extracted from a refractory ore using a conventional cyanide leaching step and with reduced cyanide consumption by pre-treating the ore prior to cyanide leaching. The refractory ore is pretreated by fine grinding and an initial leaching step which uses inexpensive limestone and lime to maintain the initial leach relatively alkaline. Oxygen is added to the initial leaching step and the conditions are carefully controlled to only partially oxidize the ground ore to between 9-15%. The initial leaching step can be carried out at temperatures of less than 100 degrees C. and at atmospheric pressures. The pre-treated ore is then leached by a conventional cyanide leaching step to recover the precious metal and cyanide consumption can be reduced by more than two thirds.

Abstract: The present invention is directed to a system for recovering metal values from metal-bearing materials. During a reactive process, a seeding agent is introduced to provide a nucleation site for the crystallization and/or growth of solid species which otherwise tend to passivate the reactive process or otherwise encapsulate the metal value, thereby reducing the amount of desired metal values partially or completely encapsulated by such material. The seeding agent may be generated in a number of ways, including the recycling of residue or the introduction of foreign substances. Systems embodying aspects of the present invention may be beneficial for recovering a variety of metals such as copper, gold, silver, nickel, cobalt, molybdenum, zinc, rhenium, uranium, rare earth metals, and platinum group metals from any metal-bearing material, such as ores and concentrates.

Abstract: A silver recovery and monitoring system including a sensor for transmitting a silver concentration signal in response to the concentration of silver in a fluid, means for determining whether the silver concentration signal indicates the concentration of silver in the fluid to be above a predetermined silver level and for initiating a silver alert signal in response to a determination that the silver concentration signal indicates the concentration of silver in the fluid to be above the predetermined silver level, and means for transmitting a notification signal to a silver monitoring station in response to the silver alert signal.

Abstract: A removal system for removing a waste metal from a waste solution. The removal system comprises outer and inner containers, inlet, intermediate, and outlet conduits, and first and second reaction media. The inner container defines an upper wall portion and is located within the outer container. The inlet conduit allows fluid to flow to the inner chamber and extends through the upper wall portion of the inner container. The intermediate conduit allows fluid flow from the inner chamber to the outer chamber. The outlet conduit allows fluid flow out of the outer chamber. The first reaction media located in the inner container. The second reaction media located in the outer container. The waste solution is forced along a removal path through the inlet conduit, the first reaction media, the intermediate conduit, the second reaction media, and the outlet conduit.

Abstract: A removal system for removing a waste metal from a waste solution. The removal system comprises outer and inner containers and inlet, intermediate, and outlet conduits. The outer container defines an outer chamber, and the inner container defines an inner chamber. The inner container is located within the outer chamber. The inlet conduit allows fluid to flow from an exterior of the outer container to the inner chamber. The intermediate conduit allows fluid flow from the inner chamber to the outer chamber. The outlet conduit allows fluid flow from the outer chamber to the exterior of the outer chamber. A first reaction media located in the inner chamber, and a second reaction media located in the outer chamber. In use, the waste solution is forced along a removal path through the inlet conduit, the first reaction media, the intermediate conduit, the second reaction media, and the outlet conduit.

Abstract: The present invention relates to an apparatus and a process for producing zinc oxide from a zinc-bearing material. The process according to the present invention comprises the steps of leaching the complex sulfide material with hydrochloric acid and oxygen; precipitating iron from the leach solution using magnesium oxide and oxygen; removing copper, silver, cadmium, cobalt and lead from the leach solution by cementation with zinc dust; precipitating zinc oxide from the leach solution using magnesium oxide; and spray roasting the remaining magnesium chloride leach solution to regenerate hydrochloric acid and magnesium oxide. The present invention further relates to processes for recovering copper, silver, lead, and iron from complex sulfide materials.

Abstract: Metal ions and/or complexes of metal ions are removed from a solution by formation of an insoluble chelated complex of the metal ions and a polymeric precipitating agent. A two-step process of mixing the influent with the precipitating agent is used to induce rapid precipitation and obtain large, self-agglomerated precipitate without addition of flocculating agent and/or pH adjustment. In addition, parallel loops are employed to simultaneously discharge treated metal-free solution and effectively collect/remove the precipitate-containing sludge without interfering with each other. The metal capturing capacity of the polymeric precipitant is maximized by forcing the influent solution through layers of the collected precipitate and by recycling unsaturated metal-precipitant complexes in the processing loop.

Abstract: Value metal, for example, silver in a spent silver bearing photographic solution is efficiently recovered in an exchange mass comprising a particulate inert substrate, for example, cellulosic fibers, synthetic fibers or sponge particles, co-mingled and interlocking with elongate particles of replacement metal, for example, strands of steel wool; the substrate defines a non-channeling random flow paths for liquid flow, and inhibits carriage of recovered value metal by the flowing liquid.

Abstract: A method for improving the recovery of gold and silver from precious metal ore is disclosed. The method comprises contacting precious metal ore with an aqueous solution containing certain fluoroaliphatic surfactants.

Abstract: An agent for treating metal ions in an aqueous solution, comprising a solid porous carrier and, supported thereon, an organic reagent (hereinafter referred to as a "redox reagent") which is capable of converting metal ions (inclusive of metal complex ions) contained in an aqueous solution to zero valent metal or monovalent metal ions by a redox reaction and which is capable of carrying out oxidation-reduction reversibly.

Abstract: An improved apparatus and method for recovering metallic silver from solutions containing silver ions by reducing silver ions and oxidizing an element in the electromotive series above silver, such as iron. The apparatus provides plug flow of solution into the reaction media and thereby eliminates the principal cause of channelling and premature failure of the media. A distribution chamber distributes solution uniformly to a porous pad of tangled threads or fibers ahead of the media. This ensures a planar flow front of solution as it enters and passes through the media. In a preferred embodiment, the pad is resilient and is supported by a highly open grating. By eliminating the flow and pressure imbalances or gradients at the entry to the media which are inherent in previous apparatus designs, the invention prevents or greatly retards the onset of channelling or plugging of the media.

Abstract: NORMs are inhibited or prevented from precipitating with scale produced by a hot aqueous solution by adding multiple portions of a crystal structure modifier to the aqueous solution as it cools before and during removal of silicon containing components by precipitation. Preferred crystal structure modifiers include polyacrylate crystal structure modifiers and phosphonomethylated amines.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. The fixer inlet discharging into a vertically oriented conduit located within the vessel, which contains iron therein and defines a gravity flow path for flow of the fixer within the vessel from the inlet to the bottom of the vessel. A layer of steel wool is positioned on the bottom of the vessel in the flow path of the fixer. Baffles inside the chamber promote mixing of the developer and fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber. A wash water inlet tube is aligned with an open ended vessel that surrounds the discharge outlet to dilute the mixed and neutralized developer and fixer.

Abstract: Radioactivity and fluoride ion are inhibited or prevented from precipitating in scale formed from a geothermal brine by adding a scale inhibitor to the cooling brine solution. Preferred scale inhibitors include polyacrylate dispersants and phosphonomethylated amines.

Abstract: The present invention provides a novel method of extracting zinc from geothermal brines and synthetic brines which can be performed in a continuous, in-line process.

Abstract: A process for separating precious metals from an MnO.sub.2, sulfidic or carbonaceous refractory ore or refractory feed such as tailings is provided. The process includes the step of leaching a feed with a leach liquor that includes an acid selected from the group of HCl and H.sub.2 SO.sub.4 in the presence of MnO.sub.2 and a reductant. A source of chloride ion is added to the leach sufficient to dissolve at least about 50% of the precious metals present in the ore. A portion of the leach is removed and precious metals are recovered from the removed portion. A portion of the chloride carrier is recycled to the leach to carry chloride values to the leach. In one embodiment, HCl is regenerated by pyrohydrolysis, which minimizes harmful waste products. The present process can advantageously avoid the use of noxious reagents.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. A baffle and long folded ribbons inside the chamber promote mixing of the developer and fixer. A source of iron ions such as fine steel wool is immersed in the fluids. Ion exchange between the steel wool and the photographic fixer recovers silver from the fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber. A wash water inlet tube is directly aligned with the discharge outlet opening in the chamber so that wash water can flow almost directly into the outlet tube to dilute the mixed and neutralized developer and fixer.

Abstract: Recovery apparatus to remove silver from solution including use of plastic chips such as are commonly used as packing materials to support scrap metal parts such as washer hole stampings in the flow path in a container between the inlet and outlet of the container.

Abstract: Geothermal brine is passed through a zone containing a packing metal so as to reduce its tendency to deposit iron/silica scale, reduce corrosivity of the brine, and/or remove and recover metals from the brine. The method polished the geothermal brine by contacting the brine with a packing metal higher in the electromotive series than silver for a time sufficient for a precious metals to precipitate onto the packing at brine temperature and pH conditions which inhibit iron-rich silica scale. Most preferably, the contacting is accomplished near an injection well at the end of a heat extraction process and the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to also act as a filter for suspended particles. Alternatively, contacting is also accomplished near the production well. Dissolving the packing in a suitable acid leaves a precious metal-rich residue behind for subsequent recovery.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time sufficient for a substantial portion of the copper and silver therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated in accordance with this method, the useful life of injection wells used to return cooled brine back to the geothermal field is extended by at least about 3 time as compared to that observed with untreated brine.

Abstract: From an ore containing gold and silver, the gold and silver are extracted by a method which comprises pulverizing the ore and bringing the pulverized ore into contact with an elemental halogen, a halogenated salt, and an organic solvent thereby converting the gold and silver into polyhalogeno anionic complexes and consequently dissolving them in the organic solvent.

Abstract: An effluent precipitation and neutralization chamber for mixing and neutralizing spent photographic developer and fixer. A baffle and long folded ribbons inside the chamber promote mixing of the developer and fixer. A source of iron ions such as fine steel wool is immersed in the fluids. Ion exchange between the steel wool and the photographic fixer recovers silver from the fixer. The desilvered fluid is diluted with wash water before it is discharged from the chamber.

Abstract: Gold and silver are extracted from their elemental state or from complex ores and alloys by leaching them with a solution containing ammonia, ammonium salts and one or more oxidants. The process is particularly effective for refractory gold ores including sulfide and carbonaceous ores.

Abstract: Equipment and methods for an efficient, low cost silver recovery apparatus for recovering silver from a silver-containing solution. The apparatus comprises a replaceable silver recovery subassembly, stackable container, lid, lock ring which is locked or sealed to make the container tamperproof, and an L-shaped connector by which an anodic silver reducing, hollow core metal coil in the replacement subassembly is releasibly connected to an effluent port of the recovery apparatus. The silver recovery subassembly comprises a mesh bag which is a carrier of the metal coil and containment filter for influent sludge and particulates produced during silver reduction. The mesh bag, with support by the container and lid provides a capturing net for incoming sludge as well as particulates which form during the silver reduction process.

Abstract: A method and apparatus for treating mineral-bearing ores and, more particularly, for treating ores containing precious metals, base metals and the like values by providing a means to extract the metal or other values from a particulated ore by classifying the ore to separate values from the gangue, and by continuously chemically leaching the said values from the ore. In accordance with an embodiment of the invention, particulated ore is fluidized and intermittently moved through a tank to classify the ore particles into strata according to size, shape and density to beneficiate values, either heavier or lighter than the gangue, for recovery of concentrated values.

Abstract: A method is disclosed for polishing geothermal brines containing iron-rich silica scale and silica particles suspended therein while removing and recovering copper, silver and other precious metals dissolved therein. The method comprises passing brine having a pH just below about 5.0 through a conduit packed with a metal higher in the electromotive series than silver for a time to sufficient for substantially all of the silver and other precious metals therein to precipitate onto the packing. Preferably, the packing comprises coiled zinc-galvanized steel chicken wire mesh packed in a sufficient density to act as a filter for said suspended particles. Dissolving the packing in a suitable acid will leave a precious metal-rich residue behind for subsequent recovery. When the brine is treated this process, the useful life of injection wells used to return cooled brine back to the geothrmal field is extended by at least about 3 times as compared to that observed with untreated brine.

Abstract: This invention concerns a process for recovering metal values from jarosite-containing materials by leaching with a calcium chloride solution at a temperature above about the atmospheric boiling point of the solution and under at least the autogenous pressure.

Abstract: A silver controller comprising a container, a core member fitted within the container, a filler material around the core member, and a fluid deflector extending around the filler material. The container has an inlet and an outlet and a base. The inlet is located at a higher level than the outlet. The core member has an aperture that is distal the base. The core member has a flange that extends outwardly above the aperture of the core member. The filler material is a metal above silver in the electromotive force series. The fluid deflector is connected to the flange and extends downwardly therefrom so as to be below the aperture in the core member. A plating shield is placed exterior of the fluid deflector. The plating shield is connected to the flange member at one end and generally abuts the bottom of the container at the other end. The plating shield is of a perforated metal suitable for allowing the passage of fluids therethrough.

Abstract: An improved canister for the recovery of silver from acidic, waste fluids is described. This canister comprises both inner and outer element, each removable from the other, with fitted top and bottom sections. The novel canister thus described, provides a rapid flow of waste material through the system and is efficient and easy to use and manufacture than prior art elements. Plugging of the canisters due to intermittent use is also reduced in the element of this invention.

Abstract: A sealed, pressurized system for processing silver bearing solutions, such as photographic solutions, for the purpose of removing the silver comprises a series of interconnected sealed containers each of which contains several spaced apart reels or masses of steel wool through which the silver bearing solution is slowly pumped under pressure and intermittently.

Abstract: The invention relates to a process for the recovery of a valuable metal(s) from its ore(s), that includes a method for removal of environmentally hazardous, volatile material prior to the removal of the metal(s) from its ore pulp or liquor carrier.The process comprises forming a pulp of particles of the ore(s) and leaching from that pulp the valuable metal component via the formation of soluble metal complexes.As elements of the leaching chemicals used are often volatile at least the liquor component of the metal containing pulp is contacted by flow of gas to remove any volatile content. In the case of the leaching chemicals volatile elements the recycling of the volatile element to reform the original leaching chemical is a substantial advantage.The metal is removed from the pulp, or its liquor component, by methods known in the art such as adsorption onto carbon or resin, electrowinning, zinc cementation, precipitation solvent extraction or the like.The metal is then recovered in its solid form.